Oil recovery vessel

ABSTRACT

A vessel for collection and salvage of oil spills having a vertically adjustable forward-mounted scoop from which fluid collected under the action of gravity and the forward motion of the vessel is directed through conduits into submerged separation tanks under conditions of laminar flow. In the submerged tanks, the fluid is separated into oil, which is transferred to storage tanks, and water which is discharged.

[451 Aug. 14, 1973 OIL RECOVERY VESSEL [75] Inventor: Eric E. Lithen,Garden City, NY.

[73] Assignee: Oil Recovery Systems, Inc., Mineola,

[22] Filed: Nov. 10, 1971 [21] Appl. No.: 197,248

3,595,392 7/1971 Martel 210/DIG. 21 3,666,102 5/1972 Blanchard 2,908,39310/1959 Lamphier 20/242 Primary ExaminerSamih .N. Zahama AssistantExaminer-T. A. Granger Attorney-Herbert Smith Sylvester U C [57]ABSTRACT 52 .S. l. In. CL 210/242 3 852; A vessel for collection andsalvage of Oil spills having [58] H H I 42 DIG 21 a verticallyadjustable forward-mounted scoop from 3 which fluid collected under theaction of gravity and the forward motion of the vessel is directedthrough conduits into submerged separation tanks under condi- [56]References Cited tions of laminar flow. In the submerged tanks, thefluid UNITED STATES PATENTS is separated into oil, which is transferredto storage Pema 210/242 tanks and water which is discharged 5 eterson210 242 3,259,245 7/1966 Earle 210/242 X 3 Claims, 4 Drawing FiguresPatented Aug. 14, 1973 3 Sheets-Sheet 1 Patented Aug. 14, 1973 3Sheets-Sheet 2 Patented Aug. 14, 1973 I5 Sheets-Sheet 5 OIL RECOVERYVESSEL This invention relates to the recovery of petroleum products fromlarge bodies of water such as the open sea. It also represents anefficient and effective means of transporting such recovered oil to acentral collection point.

The vessel described herein collects, from the surface of a large bodyof water on which the vessel is operating, a mixture of oil and waterwhich it transports to a settling system under conditions of minimalagitation and turbulence, e.g., at a Reynolds number not greater thanabout 2,000, and preferably below about 1,500, such that streamline orlaminar flow (as distinguished from turbulent flow) is maintained. Inthe settling system the upper oil layer is decanted and recovered, andthe lower, aqueous layer is returned to the said large body of water.

The invention will be more particularly described with reference to theaccompanying drawings, in which:

FIG. 1 is a plan view of the instant vessel;

FIG. 2 is a view in elevation of the vessel of FIG. 1;

FIG. 3 illustrates diagramatically the flow path of the cooling water ofthe engines of the vessel of FIGS. 1 and 2; and

FIG. 4 is a diagramatic presentation of the flow of oil and water in thenormal collection, separation, and recovery operation of the vessel ofFIGS. 1 and 2.

In the preferred embodiment illustrated in the Figures, a vessel havinga hull of generally rectangular cross-section in plan and a forwardmounted cabin I2 is provided with a blunt bow 14 having a draft somewhatgreater than the balance of the body of the hull. A scoop projectsforward from the bow and is supported from the forward face of the bowby means of a pair of swivel fittings 22. As best seen in FIG. 1, thescoop is double-throatecl, the throats each being connected by a shortconduit 24 to the swivel fitting 22.

The swivel fittings 22 each consist of an articulated pair of 90 conduitelbow segments and 32. These swivel fittings 22 are disposed below thevessels waterline 34, and the elbow segments 32 proximal to the scoopand proximate to each other are pivoted on a common hinge 38, mounted ontwo arms 40 which project forward from the bow. The centerline ofrotation of the hinge 38 is common to that of the swivel fittings 22, topermit pivoting of the scoop 20 and each of the swivel fittings 22 aboutthat centerline.

A pair of hydraulic cylinders 42 are disposed between pivots 44 and 46on the top lip of the scoop 20 and the bow 14 to raise and lower themouth of the scoop 20 respectively by pivoting the scoop about thecommon centerline of the swivel fittings 22 and hinge 38.

The elbow segments (of the swivel fittings) nearest the bow 14 areconnected to forwardly projecting flanged conduit segments 48 whichenter the bow 14 below the waterline of the empty vessel. The conduitsegments 48 discharge into an oil-water collection compartment 50disposed in the bottom of the bow. At this juncture what has beendescribed are the various parts for fluid communication between thescoop and oil-water collection compartment which may be termed first andsecond conduit means.

The oil-water collection compartment 50 is defined by the hull on itsbottom, forward, and outboard sides, and by a transverse bulkhead 52 onits aft sides. A first pair of baffles 54, located inboard of theconduit segments, aid in flow regulation and effectively divides thecollection compartment 50 into two (outboard) inlet compartments 58 anda central, primary decanting compartment 60.

The central decanting compartment 60 of the first transverse bulkhead52, inboard of the baffles 54, is provided with a primary weir 66opening into an oilwater separation compartment 70 disposed immediatelyaft of the oil-water collection compartment 50.

The separation compartment 70 is defined by the hull 10, the transversebulkhead 52, and a second transverse bulkhead 72. A second pair ofbaffles 74, disposed outboard of the primary weir 66, further aids inflow regulation and effectively divides the separation compartment intoa central receiving compartment 78 and two outboard decantingcompartments 80. The second transverse bulkhead 72 is provided with apair of final weirs 86 (disposed between the hull l0 and the baffles 74)opening into an oil collection compartment 90 defined by the hull 10,the second bulkhead 72, and a midships bulkhead 92.

The depending forward hull section of the vessel is provided with apermanent ballast 98 of concrete and steel chips to maintain submergenceof the oil-water collection compartment 50, the oil-water collectioncompartment 70, the oil collection compartment 90, and the swivelfittings 22 below the waterline 34 of the empty vessel. As may also beobserved from FIG. 2, the primary weir 66 is disposed with its bottomlip at a level below the bottom of the swivel fittings 22, and the finalweirs 86 are disposed at yet a lower level.

A watertight machinery space 100 is provided by a bottom deck I02extending from the after hull bottom to the transverse bulkhead 52, anda mid-deck 103 extending from the bulkhead 52 to the how 14. The body ofthe vessel aft of the midships bulkhead 90 is divided into oil storagecompartments 104 by appropriate bulkheads and a main deck 108.

A water-expelling first centrifugal pump is disposed within the centralprimary separation section of the oil-water collection compartment 50.The waterexpelling first centrifugal pump 120 is driven by a constantspeed hydraulic motor 122, and it has an inlet conduit 124 having itsopening at the bottom of the oilwater collection compartment 50. Thedischarge of the pump is carried downwardly and aft by a dischargeconduit 128 and is expelled below the surface of the body of water onwhich the vessel is operating aft through the hull of the depending how14 of the vessel, thereby minimizing disturbance of floating oilsurrounding the vessel and aiding forward propulsion. A hydraulicallyactuated butterfly valve 130 is located in the discharge conduit 128.

An oil-water interface sensor is located in the oilwater central primarydecanting compartment 60 below the bottom lip of the weir 66, but abovethe level of the opening of the inlet conduit 124 to the waterexpellingfirst centrifugal pump 120.

A final water-eliminating centrifugal pump is disposed in the watertightmachinery space 100. This pump is driven by a second constant speedhydraulic motoR 142, and it has an inlet conduit 144 having its openingat the bottom of the oil-water receiving compartment 70. The dischargeof this pump 140 is carried downwardly and aft by a discharge conduit148 and is expelled rearwardly through the depending bow section intothe body of water on which the vessel is operating below the surfacethereof. A hydraulically actuated butterfly valve 150 is located in thedischarge conduit 148, and an oil-water interface sensor 155 is disposedin the receiving compartment 70 below the bottom lip of the final weirs86, but above the level of the opening of the intake of the inletconduit 144 to the final water-eliminating centrifugal pump 140.

A rotary screw pump 160 is disposed within the watertight machineryspace 100, and is driven by a hydraulic motor 162. The intake of therotary pump is connected to 21 Tee 168, a first branch 170 of whichpasses through a valve 172 to the base of the oil collection compartment90. The remaining branch 174 of the Tee 168 communicates through a valve176, with the lowest point of the oil storage compartments 104.

The discharge of the rotary screw pump 160 passes to a Tee 188, thebranches of which lead, respectively, by means of appropriate conduits190 and 194, through a valve 192 to the oil storage compartments 104 andthrough a valve 196 to an oil unloading connector 198.

The oil collection compartment 90 is equipped with a low level oilsensor 200, and a high level oil sensor 202 which, respectively, arelinked to the control system for the hydraulic motor 160 and to thecontrol system for the hydraulic cylinders 42 which determine theelevation of the scoop 20. i

As indicated in FIG. 3, the scoop 20 is provided with a combinationtrash rake and grid heater 210 which keeps the scoop clear of trash andallows heating of heavy oil for ease of collection. The heating unit isconnected by flexible hose 212 and appropriate conduits to the source ofcooling medium for a starboard engine 220, which is mounted topside onthe stern of the vessel. A circulating pump 222, a three-waythermostatic valve 224, and a keep cooler 228 complete this coolingsystem.

Grid heaters 230 are also provided for the oil storage compartments 104and may be supplied with heating medium from a port diesel engine 240mounted topside on the stern or with steam from a jenny, as required. Acirculating pump 242, a three-way thermostatic valve 244, and anassociated keel cooler 248 complete the cooling system for the portengine 240.

In addition to the diesel engines 220 and 240 mounted topside on thestem, the vessel also carries on its stern, in association with eachdiesel engine, a rightangle propulsion drive unit 250. A hydraulic pump270 is coupled to the port engine, and an electric generator 280 isassociated with the starboard engine.

The oil storage compartments 104 and the watertight machinery space areprovided with air vents as appropriate.

A float 290 is vertically-adjustably disposed on each side of the scoop20, and a sensor 292 is carried forward on the scoop. This sensor 292,is employed to assist in maintaining the lower edge of the scoopapproximately 2 or 3 inches below the surface of the water duringoperation, as dictated by sea conditions.

In operation, while the vessel is underway (but not recovering oil), itstwo diesel engines 220 and 240 drive the right-angle propulsion units250 and 260 on the stern of the vessel, thereby ensuring maximum vesselspeed. During recovery of oil, however, the port propulsion unit 260 isdeclutched and the hydraulic pump 270 associated with the port dieselengine 240 is engaged to power the vessel's central hydraulic systemwhich includes, inter alia, the hydraulic motors 122, 142 and 162 fordriving the (first and second) centrifugal pumps and 140 and the rotaryscrew pump l60 respectively, rotary actuators for the butterfly valvesand 150, and the hydraulic cylinders 42 for raising and lower the scoop20.

During oil recovery, the vessel is propelled only by the starboardengine 220 through the propulsion unit 250, enabling the vessel properlyto maneuver. Additionally, the starboard diesel engine drives theelectric generator 280, providing the vessel with electrical power.

During an oil recovery operation, the height of the scoop 20 withrespect to the water is sensed by means of the sensor 292 on the scoop.As dictated by conditions sensed by the sensor, the hydraulic cylinders42 are actuated to position the scoop appropriately.

The vessel is propelled at a speed such that the mixture of oil andwater which is directed by the scoop into the hold of the vessel due tothe forward speed of the vessel and the influence of gravity on thefluid mixture is maintained in conditions of streamline flow, i.e., at aReynolds number not significantly greater than about 2,000 andpreferably below about 1,500.

The fluid medium passes from the throat of the scoop through the swivelfittings 22 into the inlet compartments 58-of the oil-water collectioncompartment 50, from which it flows through the baffles 54 into thecentral primary decanting compartment 60.

The oil-water interface in the central primary decanting section 60 ismaintained below the bottom lip of the primary weir 66 and above theentry to inlet conduit 124 of the first centrifugal pump 120. The firstcentrifugal pump, which is run at constant speed, removes water from thecompartment at a rate determined by the extent to which thehydraulically actuated butterfly valve 130 is opened. The position ofthis valve is determined by the oil-water interface sensor 135.

The oil-water interface sensor 135, in the central primary decantingcompartment, senses the cleavage between oil and water. Should thesensor indicate oil, the control system will tend to close the butterflyvalve 130 by means of hydraulic actuators, so that the oilwaterinterface will rise to the point where the sensor indicates water, atwhich time the control system will tend to open the butterfly valve.Thus, the butterfly valve 130 is continually throttled to maintain theoilwater interface at approximately the level of the sensor 135, i.e.,intermediate the bottom lip of the primary weir 66 and the intake forthe centrifugal pump 120. This is possible, of course, by virtue of thenon-positive displacement characteristic of the centrifugal pumpemployed.

Oil overflowing the primary weir 66 is discharged from the centralprimary decanting compartment 60 into the central section of theoil-water receiving cornpartment 70, from which it flows through thesecond pair of baffles 74 into the outboard decanting compartments 80.Water is eliminated from the bottom of the receiving compartment 70 bythe final watereliminating centrifugal pump and associated conduits,hydraulic motor 142, and sensor in a manner analogous to that describedin the preceding paragraph in connection with the central primarydecanting compartment.

Oil which overflows the final weirs 86 into the oil collectioncompartment 90 is pumped by the rotary screw pump 160 through theconduit 170 and opened valves 172 and 192 to the oil storagecompartments 104, the valves 176 and 196 being closed.

The inlet to the conduit 170 is approximately at the bottom of the oilcollection compartment 90, whereas the low level sensor 200 is slightlyabove the inlet to the conduit but below the level of the final weirs86. in the event the oil level in the oil collection compartment dropsbelow the low-level oil sensor 200, a signal is transmitted to thehydraulic motor 162 which drives the rotary screw oil pump 160, shuttingoff the motor.

The high-level oil sensor 202 is disposed above the final weirs 86, nearthe top of the oil collection compartment 90. In the event the oil levelin the secondary oil collection compartment reaches the high-levelsensor 202, the sensor transmits a signal which actuates the hydrauliccylinders 42 to elevate the scoop 20.

Oil may be discharged from the oil storage compartments 104 by use ofthe rotary screw pump 160 by closing valves 172 and 192 and openingvalves 176 and 196 such that the oil may enter the pump inlet throughthe conduit 174 and be discharged through the unloading connector 198.

What is claimed is:

l. A vessel for recovering oil which is floating on the surface of abody of water comprising a hull, a scoop projecting forward of said hullfor collecting a liquid mixture of said oil and water from the surfaceof said body of water, said scoop being pivotally mounted and verticallymovable to compensate for sea conditions and changes in the waterline ofsaid vessel, first and second inlet compartments disposed in said hullwith the bottom walls of said compartments substantially below thesurface of said body of water, first and second conduit means incommunication with said scoop and in respective communication with eachof said first and second inlet compartments, a first decantingcompartment constructed and arranged between said first and and secondinlet compartments in fluid communication therethrough, pump means forremoving water from adjacent the bottom walls of said first decantingcompartment, weir means comprising a wall of said first decantingcompartment with an upper edge of said weir below the horizontal planeof the first and second conduit means, a receiving component adjacentsaid weir in fluid communication with the first decanting compartment,second and third decanting components constructed and arranged onopposite ends of said receiving compartment and in fluid communicationwith said receiving compartment through said opposite ends of saidcompartment, weir means comprising a wall of each of said second andthird decanting compartments with an upper edge of each of said weirsbelow the upper edge of said weir between said first decantingcompartment and said receiving compartment, an oil collectioncompartment constructed and arranged in fluid communication with saidsecond and third decanting compartments and adapted to receive oil overthe upper edges of said weir means of each of said second and thirddecanting compartment, pump means for removing collected oil from saidoil collection compartment.

2. A vessel as set forth in claim 1 wherein said vessel is powered by aheat producing engine being cooled by a liquid circulating means, meansfor heating said scoop by means of said liquid.

3. A vessel as set forth in claim 1 wherein said pump means for removingwater from adjacent the bottom walls of said first decanting compartmentincludes sensor means responsive to the quantity of water in said firstdecanting compartment whereby a pump of said pump means operates toremove water from said first decanting compartment at a rate sufficientto maintain the level of the water therein below the weir meanscomprising a wall of said first decanting compartment. k F t

1. A vessel for recovering oil which is floating on the surface of abody of water comprising a hull, a scoop projecting forward of said hullfor collecting a liquid mixture of said oil and water from the surfaceof said body of water, said scoop being pivotally mounted and verticallymovable to compensate for sea conditions and changes in the waterline ofsaid vessel, first and second inlet compartments disposed in said hullwith the bottom walls of said compartments substantially below thesurface of said body of water, first and second conduit means incommunication with said scoop and in respective communication with eachof said first and second inlet compartments, a first decantingcompartment constructed and arranged between said first and second inletcompartments in fluid communication therethrough, pump means forremoving water from adjacent the bottom walls of said first decantingcompartment, weir means comprising a wall of said first decantingcompartment with an upper edge of said weir below the horizontal planeof the first and second conduit means, a receiving component adjacentsaid weir in fluid communication with the first decanting compartment,second and third decanting components constructed and arranged onopposite ends of said receiving compartment and in fluid communicationwith said receiving compartment through said opposite ends of saidcompartment, weir means comprising a wall of each of said second andthird decanting compartments with an upper edge of each of said weirsbelow the upper edge of said weir between said first decantingcompartment and said receiving compartment, an oil collectioncompartment constructed and arranged in fluid communication with saidsecond and third decanting compartments and adapted to receive oil overthe upper edges of said weir means of each of said second and thirddecanting compartment, pump means for removing collected oil from saidoil collection compartment.
 2. A vessel as set forth in claim 1 whereinsaid vessel is powered by a heat producing engine being cooled by aliquid circulating means, means for heating said scoop by means of saidliquid.
 3. A vessel as set forth in claim 1 wherein said pump means forremoving water from adjacent the bottom walls of said first decantingcompartment includes sensor means responsive to the quantity of water insaid first decanting compartment whereby a pump of said pump meansoperates to remove water from said first decanting compartment at a ratesufficient to maintain the level of the water therein below the weirmeans comprising a wall of said first decanting compartment.